commit

main.go

@@ -0,0 +1,132 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/user"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+var (
+	blockedWords []*regexp.Regexp
+	redaction    = "redacted"
+)
+
+func checkBlockedWordsFilePerm(path string) {
+	info, err := os.Stat(path)
+	if err != nil {
+		log.Fatalf("Failed to stat %s: %v", path, err)
+	}
+
+	mode := info.Mode().Perm()
+	if mode != 0o700 {
+		log.Fatalf("Permission on %s must be 700, found %o", path, mode)
+	}
+}
+
+func loadBlockedWords(path string) {
+	file, err := os.Open(path)
+	if err != nil {
+		log.Fatalf("Failed to open %s: %v", path, err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		if strings.HasPrefix(line, "redaction:") {
+			if redaction != "redacted" {
+				log.Fatalf("Multiple redaction definitions found in %s", path)
+			}
+			redaction = strings.TrimSpace(strings.TrimPrefix(line, "redaction:"))
+			continue
+		}
+		blockedWords = append(blockedWords, regexp.MustCompile(regexp.QuoteMeta(line)))
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Error reading %s: %v", path, err)
+	}
+}
+
+func censorLine(line string) string {
+	for _, re := range blockedWords {
+		line = re.ReplaceAllString(line, redaction)
+	}
+	return line
+}
+
+func process(input io.Reader, output io.Writer) {
+	scanner := bufio.NewScanner(input)
+	writer := bufio.NewWriter(output)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(strings.TrimSpace(line), "#") {
+			fmt.Fprintln(writer, line)
+			continue
+		}
+		censored := censorLine(line)
+		fmt.Fprintln(writer, censored)
+	}
+	writer.Flush()
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Error reading input: %v", err)
+	}
+}
+
+func main() {
+	if len(os.Args) == 1 && isInputFromTerminal() {
+		fmt.Fprintln(os.Stderr, "No input provided. Exiting.")
+		os.Exit(1)
+	}
+
+	usr, err := user.Current()
+	if err != nil {
+		log.Fatalf("Unable to determine current user: %v", err)
+	}
+	confPath := filepath.Join(usr.HomeDir, ".blocked_words.txt")
+	checkBlockedWordsFilePerm(confPath)
+	loadBlockedWords(confPath)
+
+	switch len(os.Args) {
+	case 1:
+		process(os.Stdin, os.Stdout)
+	case 2:
+		inFile, err := os.Open(os.Args[1])
+		if err != nil {
+			log.Fatalf("Cannot open input file: %v", err)
+		}
+		defer inFile.Close()
+		process(inFile, os.Stdout)
+	case 3:
+		inFile, err := os.Open(os.Args[1])
+		if err != nil {
+			log.Fatalf("Cannot open input file: %v", err)
+		}
+		defer inFile.Close()
+		outFile, err := os.Create(os.Args[2])
+		if err != nil {
+			log.Fatalf("Cannot create output file: %v", err)
+		}
+		defer outFile.Close()
+		process(inFile, outFile)
+	default:
+		log.Fatalf("Usage: %s [input_file] [output_file]", os.Args[0])
+	}
+}
+
+func isInputFromTerminal() bool {
+	fileInfo, err := os.Stdin.Stat()
+	if err != nil {
+		return true
+	}
+	return (fileInfo.Mode() & os.ModeCharDevice) != 0
+}
+